<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>DOM改变HTMLCSS</title>
</head>
<body>
    <h1 id="id1">
        我的标题 1
    </h1>

    <button type="button" onclick="document.getElementById('id1').style.color='red'">
        点我!
    </button>

</body>
</html>